Head & Neck Surgery Course Parapharyngeal space: surgical anatomy Dr Pierfrancesco PELLICCIA Pr Benjamin LALLEMANT Service ORL et CMF CHU de Nîmes CH de Arles Introduction • Potential deep neck space • Shaped as an inverted pyramid • Base of the pyramid: skull base • Apex of the pyramid: greater cornu of the hyoid bone Introduction • 2 compartments – Prestyloid – Poststyloid Anatomy: boundaries • Superior: small portion of temporal bone • Inferior: junction of the posterior belly of the digastric and the hyoid bone Anatomy: boundaries Anatomy: boundaries • Posterior: deep fascia and paravertebral muscle • Anterior: pterygomandibular raphe and medial pterygoid muscle fascia Anatomy: boundaries • Medial: pharynx (pharyngobasilar fascia, pharyngeal wall, buccopharyngeal fascia) • Lateral: superficial layer of deep fascia • Medial pterygoid muscle fascia • Mandibular ramus • Retromandibular portion of the deep lobe of the parotid gland • Posterior belly of digastric muscle • 2 ligaments – Sphenomandibular ligament – Stylomandibular ligament Aponeurosis and ligaments Aponeurosis and ligaments • Stylopharyngeal aponeurosis: separates parapharyngeal spaces to two compartments: – Prestyloid – Poststyloid • Cloison sagittale: separates parapharyngeal and retropharyngeal space Aponeurosis and ligaments Stylopharyngeal aponeurosis Muscles stylohyoidien Stylopharyngeal , And styloglossus muscles Prestyloid compartment Contents: – Retromandibular portion of the deep lobe of the parotid gland – Minor or ectopic salivary gland – CN V branch to tensor veli palatini muscle – Ascending pharyngeal artery and venous plexus – Most fat Poststyloid compartment Contents – Carotid artery – Internal jugular vein – CN IX to XII – Cervical sympathetic chain – Glomus tissues Parapharyngeal space: keep in mind • Suprahyoid • Boundaries – Superior—skull base – Inferior—hyoid – Anterior—ptyergomandibular raphe – Posterior—prevertebral fascia – Medial—buccopharyngeal fascia – Lateral—superficial layer of deep fascia Parapharyngeal space: keep in mind • 2 compartments: Prestyloid • Muscular compartment • Medial—tonsillar fossa • Lateral—medial pterygoid • Contains fat, connective tissue, nodes Poststyloid • Neurovascular compartment • Carotid sheath • Cranial nerves IX, X, XI, XII • Sympathetic chain • Stylopharyngeal aponeurosis – Prevents infectious spread from anterior to posterior Parapharyngeal space relationships • Communicates with several deep neck spaces. – Parotid – Masticator – Peritonsillar – Submandibular – Retropharyngeal Retropharyngeal Space • Entire length of neck • Boundaries: – Anterior border - pharynx and esophagus (buccopharyngeal fascia) – Posterior border - alar layer of deep fascia – Superior border - skull base – Inferior border – superior mediastinum • Combines with buccopharyngeal fascia at level of T1-T2 – Lateral border – cloison sagittale – Midline raphe connects superior constrictor to the deep layer of deep cervical fascia. • Contains retropharyngeal nodes. Danger Space • Extends from skull base to diaphragm • Boundaries – Anterior border - alar layer of deep fascia – Posterior border - prevertebral layer • Contains loose areolar tissue. Prevertebral Space • Entire length of vertebral column • Boundaries – Anterior border - prevertebral fascia – Posterior border - vertebral bodies and deep neck muscles – Lateral border – transverse processes Head & Neck Surgery Course Parapharyngeal space: surgical options and technique Dr Pierfrancesco PELLICCIA Pr Benjamin LALLEMANT Service ORL et CMF CHU de Nîmes CH de Arles Surgical Options • Transparotid approach • Transcervical approach • Cervical-parotid approach • Cervical-transpharyngeal (mandibular swing) Transparotid approach • For deep lobe of parotid lesion • Superficial parotidectomy with facial nerve preservation • Retract facial nerve from the deep parotid lobe • Dissect posterior and inferior around mandible • Improve access by mandibulotomy Transparotid approach Transparotid approach (Total parotidectomy + SND of levels II-III for parotid cancer) Transcervical approach • For poststyloid tumor • Transverse incision at level of hyoid • Submandibular gland removed or retracted • Incision through the fascia deep to the submandibular space • Increase exposure by releasing digastric, stylohyoid, styloglossus from hyoid, cut stylomandibular ligament, mandibulotomy Cervical-parotid approach • Extend cervical incision up infront of ear • Identify facial nerve • Divide posterior belly digastric • Divide styloglossus, stylohyoid close to styloid process • Divide stylomandibular ligament • Can combine with mandibulotomy Cervical-parotid approach Indications • Can be used to remove majority of the parapharyngeal tumor – All deep lobe parotid tumors and extraparotid salivary tumors – Low grade malignant tumors of deep lobe of parotid – Many poststyloid tumors, including most neurogenic tumors and small paragangliomas Cervical-transpharyngeal (mandibular swing) • “Mandibular swing” • Midline lip splitting or visor flap • Mandibulotomy anteriorly, incise along floor of mouth to anterior tonsillar pillar • Identify hypoglossal nerve and lingual nerve • Divide styloglossus and stylopharyngeus muscle • Need tracheotomy Cervical-transpharyngeal (mandibular swing) Indications • All vascular tumors that extend into the superior portion of the parapharyngeal space • Malignant tumor invaded skull base or vertebral body .